1. Field of the Invention
The present invention relates generally to spring drives or motors, including flat (or spiral coil) and coil spring drives, which are useful in numerous applications, to other components which are useful in combination with such spring drives, and, in particular, to the application of such spring drives and components and combinations thereof to window cover systems.
2. Definitions and Applicability
Springs of the type shown for example in FIGS. 5C, 7C, 9C and 10C typically are referred to herein as coil springs. Springs of the type shown for example in FIGS. 6-8 typically are referred to herein as flat springs.
Typically, as used herein, the word xe2x80x9ccoverxe2x80x9d refers to expandable or extendible structures such as blinds and drapes. These include slat structures such as so-called Venetian or slat blinds and so-called mini-blinds. These structures also include pleated folding structures such as single and plural pleat structures and box, hollow and cellular structures. xe2x80x9cCoverxe2x80x9d also refers to flat, sheet-type covers such as roller blinds. In this document, xe2x80x9ccoverxe2x80x9d and xe2x80x9cblindxe2x80x9d are frequently used interchangeably. As applied to such covers, xe2x80x9coperatexe2x80x9d refers to the process of closing and opening the covers, typically (for horizontally oriented or extending covers with the cover mounted and collected at the top) to lowering and raising the cover.
As used here, xe2x80x9chorizontalxe2x80x9d window cover refers to horizontally oriented covers such as horizontal slat blinds, horizontal folded-pleat blinds and drapes and horizontal cellular blinds and drapes. The present invention is applicable generally to horizontal window cover systems and to flat window cover systems. It is understood that xe2x80x9cwindow,xe2x80x9d as used for example in xe2x80x9cwindow cover,xe2x80x9d includes windows, doorways, openings in general and non-opening areas or regions to which covers are applied for decoration, display, etc.
As used here, the terms xe2x80x9coperatively connected,xe2x80x9d xe2x80x9coperatively coupled,xe2x80x9d operatively connected or coupled and the like include both direct connections of one component to another without intervening components and connections via intervening components including gears, transmissions, etc. Also, xe2x80x9cpluralityxe2x80x9d means two or more.
3. Current State of the Relevant Technology
a. Slat and Resilient ((Pleated) Blinds
Typically a horizontal cover or blind is mounted above the window or space which is to be covered, and is operated using lift cords to extend the cover and lower it across the area, stopping at a selected position at which the blind partially or fully covers the area. For typical horizontal slat blinds, the lift cords are attached to a bottom rail and the xe2x80x9crungsxe2x80x9d or cross-members of a separate cord ladder are positioned beneath the slats of the blind. When the blind is fully lowered, each slat is supported by a rung of the blind""s cord ladder and relatively little weight is supported by the lift cords. However, as the blind is raised, the slats are xe2x80x9ccollectedxe2x80x9d on the bottom rail, and the support of the slats is thus increasingly transferred from the cord ladder to the bottom rail and the weight supported by the rail and the associated lift cords increases.
Many pleated, cellular, box, etc., blinds are formed of resilient material having inherent spring-like characteristics. As the resilient pleated blind is raised toward the fully open position, the blind material is increasingly compressed, and requires increasingly greater force to overcome the compression force and move the blind and hold the blind in position. Conversely, as the blind is extended and lowered toward a closed position, the compression of the pleats decreases. Effectively, then, both the slat blind and the pleated blind require increasingly greater force to open or raise the blind and to maintain the blind open than is required to close or lower the blind and maintain the blind closed.
b. Flat and Coil Spring Drives
The operating characteristics of conventional coil spring drives and conventional constant torque flat spring drives are not ideally suited to assist the opening and closing operation of horizontal and flat blinds, especially long or heavy blinds. As applied to downward-closing embodiments of such blinds, such spring drives usually are mounted at the top of the blind, and are operatively connected or coupled to the shaft about which the blind lift cords are wound. As described above, as the blind is lowered, the slat weight supported by the lift cords decreases and the compression of the pleats decreases.
However, in the case of the constant torque flat spring drive, as the blind is lowered (or raised) the torque force of the spring remains relatively constant as the supported slat weight or compression force of the lowering blind decreases, with the result that the spring torque may overcome the decreasing supported weight or the decreasing compression force, and raise the blind in fast, uncontrolled fashion. Also, it may be difficult to keep the blind at a selected position. Furthermore, if the blind is heavy, and requires a strong spring to maintain the blind open, the blind may be particularly susceptible to instability and uncontrolled raising operation when partially or fully extended (closed).
In the case of the coil spring drive, as the blind is lowered, the spring is wound and the energy stored in the coil spring increases, with the result that the increasing torque or force of the spring may then overcome the decreasing supported weight or the decreasing compression force and raise the blind in fast, uncontrolled fashion. Also, and as stated above regarding flat spring-assisted blinds, it may be difficult to keep coil spring-assisted blinds at a selected position and, if the blind is heavy and requires a strong spring to maintain the blind open, the blind may be particularly susceptible to instability and uncontrolled raising operation when partially or fully extended (closed). Conversely, when the coil spring-connected blind is at or near the upper limit of its travel (i.e., is open), the slat weight supported by the lift cords and the pleat compression are at or near maximum, while the coil spring torque is at or near minimum.
Frequently, prior art coil spring drives use latching mechanisms in an attempt to hold the blind or cover in position.
1. In General
In one aspect, the present invention is embodied in various embodiments of selected devices and components, including operating mechanisms selected from spring drives including flat spring drives and coil spring drives, motors including electric motors, including battery, solar, etc. powered electric motors, cranks and pulley cord be power transfer systems including gear systems and transmissions, band or cord systems and transmissions including varied ratio systems or transmissions, and gear sets; and braking devices or mechanisms including detent, magnetic and recoiler brakes. In another aspect, the present is embodied in combinations comprising a plurality of the selected devices and components.
In yet another aspect, the present invention is embodied in various spring drive systems which incorporate one or a combination of operating mechanisms and in combinations of such operating mechanisms with one or more of the other devices and components.
In still another aspect, the present invention is embodied in window cover systems which incorporate various embodiments of the selected devices and components, in window cover systems including combinations comprising a plurality of the selected devices and components, in window cover systems comprising one or a combination of the selected operating mechanisms and components, and in window cover systems comprising combinations of such operating mechanisms with one or more of the other selected devices and components.
2. Flat Spring (Flat Spring; Varying Torque; Cove or Holes)
In yet another specific embodiment, the present invention is embodied in a spring drive unit comprising a storage drum or spool, an output drum or spool, and a flat spring wound on the two drums or spools. In a preferred embodiment, the flat spring is adapted for providing a torque which varies along at least a section of the length of the spring. In a specific embodiment, at least one section of the spring has a cove or transverse curvature which selectively varies along at least a section of the length of the spring for providing torque which varies proportional as the spring winds and unwinds. In another specific embodiment, at least one section of the spring has holes of selected size and location along its longitudinal axis for providing torque which varies proportional to the transverse size of the holes and the resulting effective cross section of the spring as the spring winds and unwinds.
Other embodiments of flat spring drives in accordance with the present invention, not exhaustive, include constant cove section(s); and/or sections selected from varying cove(s), including reverse curvature cove(s); and/or perforated section(s).
In another embodiment, the spring drive further comprises a magnetic brake comprising one or more magnetizable regions or magnets at selected positions along the flat spring, or at least one of the flat springs; and a magnet brake member preferably mounted adjacent the flat spring, so the brake member stops for stopping the flat spring at the selected positions.
In yet another embodiment, the spring drive further comprises a detent brake comprising one or more holes at selected positions along the flat spring, or at least one of the flat springs; and a detent brake member for engaging the holes and stopping the flat spring at the selected positions.
Still additional specific embodiments of the present invention include individual spring drives comprising plural springs, and spring drive systems comprising plural spring drive units, including individual spring drive units which comprise single or plural springs.
In another embodiment, the present invention is embodied in a plural spring drive system comprising an output drum; and a plurality of storage drums, each having a flat spring wound thereon. The plurality of flat springs extend to and are wound together in overlapping fashion on the output drum, such that the system torque at the output drum is a multiple of the torques associated with the individual flat springs. Various alternative arrangements include, for example, storage drums arranged in approximately a straight line;output drum and storage drums arranged in approximately a straight line; storage drums arranged in a cluster; and output drum and storage drums arranged in a cluster. In a preferred embodiment, at least one of the flat springs is adapted for imparting a torque component to the system torque which varies along at least a section of the length of the said one spring.
The present invention is also embodied in window cover systems which include one or more spring drives of the type described above and herein.
In specific applications embodying the present invention, one or more of the spring drives and/or one or more of the other devices and components descried above and herein are incorporated in window cover systems for providing torque or force tailored to the operating characteristics of the cover. For example, the spring drive (or drives) is used in combination with at least one device or component selected from one or more band shift transmissions for varying the drive force of the spring; one or more gear transmissions for providing a fixed gear ratio for fixedly altering the drive force of the spring; and one or more connecting gear sets and mechanisms. In addition to controlling the applied force of the spring, the transmissions alter the length of the cover and provide inertia and friction for maintaining the blind at selected positions between and including open and closed positions.
3. Coil Spring
a. Coil Spring Drive and Gear Transmission (and Optional Band Transmission)
In yet another, specific aspect, the present invention is embodied in a spring drive system comprising a coil spring mounted around a shaft and having a fixed end and a rotatable end; and a gear transmission of fixed drive ratio, operatively connected at one end to the rotatable spring end and operatively connected at the opposite end to the shaft. As a result of this arrangement, the transmission applies the fixed drive ratio between the coil spring and the shaft, determining the ratio of the shaft rotational distance to the spring winding distance and thereby controlling the force applied to the shaft by the spring. In another related aspect, the spring drive system comprising the coil spring drive and the gear transmission further comprises a band transmission of continuously varying drive ratio, which is itself operatively connected at one end to the rotatable spring end and operatively connected at the opposite end to the shaft, for applying the continuously varying drive ratio between the coil spring and the shaft to continuously vary the force applied to the shaft by the spring and to continuously vary the ratio of the shaft rotational distance and the spring winding distance.
b. Coil Spring Drive and Band Transmission (and Optional Gear Transmission)
In another aspect, the present invention is embodied in a spring drive unit comprising a coil spring mounted around a shaft and having a fixed end and a rotatable end; and a band transmission of continuously varying drive ratio, operatively connected at one end to the rotatable spring end and operatively connected at the opposite end to the shaft. As a result of this arrangement, the band transmission applies said continuously varying drive ratio between the coil spring and the shaft to continuously vary the force applied to the shaft by the spring and to continuously vary the ratio of the shaft rotational distance and the spring winding distance. In another related aspect, the spring drive system comprising the coil spring drive and the band transmission further comprises a gear transmission of given drive ratio, which itself is operatively connected at one end to the rotatable spring end and is operatively connected at the opposite end to the shaft, for applying the given drive ratio between the coil spring and the shaft to fixedly alter the force applied to the shaft by the spring and to fixedly alter the varying ratio of the shaft rotational distance to the spring winding distance, and for applying inherent holding friction to the shaft.
c. Window Cover System: Coil Spring Drive and Gear Transmission
In another specific aspect, the present invention is embodied in a window cover system comprising an extendible window cover; lift means operatively connected to the cover for extending and retracting the extendible cover to selected positions; and a spring drive system connected to the lift means for assisting the extending and retracting of the cover. The spring drive system comprises a coil spring mounted around a shaft and having a fixed end and a rotatable end; and a gear transmission of given (fixed) drive ratio, the transmission connected at one end to the rotatable spring end and at the opposite end to the lift means. As a result of this arrangement, the transmission applies holding friction to the lift means-supported cover and applies the given drive ratio between the coil spring and the lift means, determining the ratio of the cover travel distance to the spring winding distance as the cover is extended and retracted, thereby controlling the force applied to the cover by the spring.
d. Window Cover System: Coil Spring Drive and Band Transmission
In yet another specific aspect, the present invention is embodied in a window cover system comprising an extendible window cover; lift means operatively connected to the cover for extending and retracting the cover to selected positions; and a spring drive system connected to the lift means for assisting the extending and retracting of the cover. The spring drive system comprises a coil spring mounted along a shaft and having a fixed end and a rotatable end; and a band shift transmission of varying drive ratio. The band shift transmission is connected at one end to the rotatable coil spring end and at the opposite end to the lift means. As a result, the band shift transmission applies said varying drive ratio between the coil spring and the lift means, thereby varying the ratio of the cover travel distance to the spring winding distance as the cover is extended and retracted, thereby controlling the force applied to the cover by the spring.
In another aspect, the spring drive unit further comprises gear means connecting the coil spring to the band shift transmission. The gear means comprises a set of bevel gears and a second set of gears, preferably direct gears. The bevel gears are operatively connected between the spring rotation end and one end of the direct gears, specifically the bevel gears are connected at one end to the spring free end for rotation therewith and at the opposite end mesh with one end of the direct gears for rotation therewith. The direct gears are connected at the opposite end to one end of the band shift transmission for rotation therewith. The opposite end of the band shift transmission is connected to the lift cord pulleys for rotation therewith. As a result of this arrangement, the gear means applies holding friction to the lift cord-supported cover. Also, the gear means has a given (fixed) drive ratio which further contributes to the overall ratio of the cover travel distance to the spring winding distance and so controls the force applied to the cover by the spring.
In yet another aspect, the gear means comprises a gear transmission of given drive ratio, which is connected between the band shift transmission and the direct gear set, with one end of the transmission connected to said opposite end of the direct gear set and the opposite end of the transmission connected to said one end of the band shift transmission. The gear transmission thereby applies additional holding friction to the lift cord-supported cover and applies the given ratio between the coil spring and the lift cord, further changing the overall ratio of the cover travel distance to the spring winding distance and the force applied to the cover by the coil spring.
Other aspects and embodiments of the present invention are described in the specification, drawings and claims.